Sean Klepper M.D.
Artur Zembowicz M.D....
- Caused by the fungus Sporothrix schenckii
- "Rose gardener's disease": Sporothrix organisms found on plants are inoculated into the hand by penetrating trauma.
- A hard nodule develops at the site of inoculation and the infection moves up the upper extremity by way of the lymphatics, with resulting regional lymphadenopathy.
- The diagnosis is best made by culture, since the organism is difficult to find histologically.
- Early lesions show a nonspecific mixed inflammatory infiltrate.
- Later lesions may show suppurative granulomas with concentric zones: central neutrophilic microabscesses surrounded by epithelioid macrophages, which are in turn surrounded by lymphocytes and plasma cells.
- Asteroid bodies may be seen, and are characteristically extracellular, in contrast to the intracellular asteroid bodies seen in sarcoidosis and other granulomatous diseases.
- If the organisms are visible on fungal stains, they appear as 3-8-micron round to cigar-shaped yeasts.